Bismuth Complexes Research Articles

Advances of Inorganic Materials in the Detection and Therapeutic Uses against Coronaviruses

Coronaviruses (CoVs) are enveloped viruses with particle-like characteristics and a diameter of 60-140 nm, positively charged, and single-stranded RNA genomes which produce a major outbreak of human fatal pneumonia since the beginning of the 21st century. COVID-19 is currently considered as a continuous potential pandemic threat across the globe. Therefore, considerable efforts have been made to develop innovative methods and technologies for suppressing the spread of viruses as well as inactivating the viruses but COVID-19 vaccines are still in the development phase. This perspective focuses on the sensing, detection and therapeutic applications of CoVs using inorganic-based nanomaterials, metal complexes, and metal-conjugates. Synthetic inorganic-based nanoparticles interact strongly with proteins of viruses due to their morphological similarities, and therefore, numerous antivirals have been tested for efficacy against different viruses in vitro through colorimetric and electrochemical assays. Metal complexes-based agents such as bismuth complexes form attractive class of drugs with a number of therapeutic applications including the inhibition and duplex-unwinding activity of SARS-CoV helicase by quantitative real-time PCR (Q-RT-PCR), phosphate release assay and radioassay studies. Metal-conjugates show major effects on inhibiting the 3C-like protease of SARS-CoV and the replication of RNA-dependent RNA polymerase (RdRp). We anticipate that these approaches will provide rapid and accurate antiviral strategies in the development of these innovative sensors for the detection, inhibition and antiviral activities of coronaviruses.

Carbodicarbene Bismaalkene Cations: Unravelling the Complexities of Carbene versus Carbone in Heavy Pnictogen Chemistry.

We report a combined experimental and theoretical study on the first examples of carbodicarbene (CDC)‐stabilized bismuth complexes, which feature low‐coordinate cationic bismuth centers with C=Bi multiple‐bond character. Monocations [(CDC)Bi(Ph)Cl][SbF6] (8) and [(CDC)BiBr2(THF)2][SbF6] (11), dications [(CDC)Bi(Ph)][SbF6]2 (9) and [(CDC)BiBr(THF)3][NTf2]2 (12), and trication [(CDC)2Bi][NTf2]3 (13) have been synthesized via sequential halide abstractions from (CDC)Bi(Ph)Cl2 (7) and (CDC)BiBr3 (10). Notably, the dications and trication exhibit C⇉ Bi double dative bonds and thus represent unprecedented bismaalkene cations. The synthesis of these species highlights a unique non‐reductive route to C−Bi π‐bonding character. The CDC‐[Bi] complexes (7–13) were compared with related NHC‐[Bi] complexes (1, 3–6) and show substantially different structural properties. Indeed, the CDC ligand has a remarkable influence on the overall stability of the resulting low‐coordinate Bi complexes, suggesting that CDC is a superior ligand to NHC in heavy pnictogen chemistry.

Carbodicarbene Bismaalkene Cations: Unravelling the Complexities of Carbene versus Carbone in Heavy Pnictogen Chemistry

AbstractWe report a combined experimental and theoretical study on the first examples of carbodicarbene (CDC)‐stabilized bismuth complexes, which feature low‐coordinate cationic bismuth centers with C=Bi multiple‐bond character. Monocations [(CDC)Bi(Ph)Cl][SbF6] (8) and [(CDC)BiBr2(THF)2][SbF6] (11), dications [(CDC)Bi(Ph)][SbF6]2 (9) and [(CDC)BiBr(THF)3][NTf2]2 (12), and trication [(CDC)2Bi][NTf2]3 (13) have been synthesized via sequential halide abstractions from (CDC)Bi(Ph)Cl2 (7) and (CDC)BiBr3 (10). Notably, the dications and trication exhibit C Bi double dative bonds and thus represent unprecedented bismaalkene cations. The synthesis of these species highlights a unique non‐reductive route to C−Bi π‐bonding character. The CDC‐[Bi] complexes (7–13) were compared with related NHC‐[Bi] complexes (1, 3–6) and show substantially different structural properties. Indeed, the CDC ligand has a remarkable influence on the overall stability of the resulting low‐coordinate Bi complexes, suggesting that CDC is a superior ligand to NHC in heavy pnictogen chemistry.

Synthesis, structural characterization, and molecular docking studies of bioactive bismuth(III) complexes with substituted hydrazones

Eight new bismuth(III) complexes (1-8) of substituted hydrazones having general formula; [Bi(RCONHNCHC5H4N)Clx] and [Bi(RCONHNCHC9H6N)Clx], where R = C10H7O (1, and 8), C4H3S (2), C6H5O (3, and 6), C7H7(4), C5H4N (5, and 7), x = 2 or 3 have been prepared. The substituted hydrazones (I1-I8) were synthesized by reacting the stoichiometric amounts of the respective hydrazides such as p-toluic hydrazide, 4-hydroxybenzhydrazide, thiophene-2-carboxylic acid hydrazide, 3-hydroxy-2-naphthoic acid hydrazide, Isonicotic acid hydrazide and appropriate aromatic aldehydes like pridine-2-carboxaldehyde and quinoline-2-carboxyaldehyde. These hydrazones (ligands),then complexed to Bi(III) species to yield the target compounds. They were characterized by FTIR, and NMR spectroscopy to find out an explicit evidence about their structural motifs. The X-ray data for (1 & I6) further validate the chemical structures of the synthesized compounds. The molecular geometry for (1) is predominately distorted pentagonal bipyramidal where hepta-coordinated Bi(III) center is attached to the nitrogens of pyridine and of azomethine moieties along with the carbonyl oxygen, two chloro and two oxygens of the (two) DMSO molecules. The bond lengths for Bi(1)-O(1), Bi(1)-N(1) and Bi(1)-N(2) are 2.323(5), 2.539(6), 2.390(5) oA respectively indicating Bi(1)-O(1) as the strongest linkage to the metal center. The H-bonding, present in (1), contributed an extra stability to the structure. The synthesized compounds were initially screened for their possible antimicrobial, alpha-amylase, and protein kinase inhibition, some (1,2,6,8) exhibit significant activity. The experimental results are further endorsed by molecular docking studies against helicobacter pylori urease (1E9Y), epidermal growth factor receptor tyrosine kinase (1M17) and human pancreatic alpha amylase (5U3A) inhibition activity. The significant ligand-receptor interactions, observed at the binding pocket of the selected drug targets, further revealed the enzyme inhibition potential of the compounds and highlighting their possible roles as therapeutic agents in future drug discovery processes.

A new C-anionic tripodal ligand 2-{bis(benzothiazolyl)(methoxy)methyl}phenyl and its bismuth complexes.

A new tripodal C-anionic ligand, 2-{bis(benzothiazolyl)(methoxy)methyl}phenyl (L), was stably generated by the reaction of the ligand precursor (L'), the corresponding bromide (2-BrC6H4)(MeO)C(C7H4NS)2 (C7H4NS = 2-benzothiazolyl), with nBuLi at -104 °C in the presence of TMEDA (N,N,N',N'-tetramethylethylenediamine). The ligand lithium salt reacted with BiCl3 to give a 2 : 1 complex L2BiCl. A 1 : 1 complex LBiCl2 was obtained in good yield by the redistribution reaction between L2BiCl and BiCl3. X-ray diffraction analysis revealed that the ligand L coordinated in an expected κ3-C,N,N' coordination mode in LBiCl2, while it coordinated in κ3-C,N,O and κ2-C,O coordination modes in L2BiCl. The ligand precursor reacted with BiX3 (X = Cl, Br) to give 1 : 1 complexes L'BiX3 and was found to act as a neutral tripodal C(π),N,N-ligand.

Organohalide Precursors for the Continuous Production of Photocatalytic Bismuth Oxyhalide Nanoplates.

Metal heteroanionic materials, such as oxyhalides, are promising photocatalysts in which band positions can be engineered for visible-light absorption by changing the halide identity. Advancing the synthesis of these materials, bismuth oxyhalides of the form BiOX (X = Cl, Br) have been prepared using rapid and scalable ultrasonic spray synthesis (USS). Central to this advance was the identification of small organohalide molecules as halide sources. When these precursors are spatially and temporally confined in the aerosol phase with molten salt fluxes, powders composed of single-crystalline BiOX nanoplates can be produced continuously. A mechanism highlighting the in situ generation of halide ions is proposed. These materials can be used as photocatalysts and provide proof-of-concept toward USS as a route to more complex bismuth oxyhalide materials.

Structural and biological features of bismuth(III) halide complexes with heterocyclic thioamides

Ten novel bismuth(III) halide complexes of [Bi(L)X3]n, [Bi(L)2×3]2, and [Bi(L)3×3] structural types were synthesized, in which L: 5-ethoxy-2-mercaptobenzimidazole, 5‑methoxy-2-mercaptobenzimidazole and N-methylbenzothiazole. Bismuth(III) halide complexes 1–10 were characterized by melting point, elemental analysis, molar conductivity, FT-IR, FT-Raman, UV-Visible, 1H and 13C NMR spectroscopic techniques, as well as by the Thermogravimetric-Differential Thermal Analysis (TG-DTA). The crystal structures of complexes 1–10 were determined by using single crystal X-ray diffraction study. The results show that the bismuth(III) complexes exist as monomer (4), doubly-bridged dimer (1–3 and 5–9), and edge-sharing polymer (10), in which the central bismuth atom is a six-coordinated and adopts distorted octahedral geometries. We report here, for the first time, cis-sulfur, cis-halide arrangement of the doubly-bridged dimer bismuth(III) complexes. The intermolecular interactions in bismuth(III) complexes play a very important role in the supramolecular architecture. A detailed analysis of the intermolecular interactions has been performed as based on the Hirshfeld surfaces and their associated two-dimensional fingerprint plots. Bismuth(III) halide complexes 1–10 and their free ligands have been screened for antimicrobial activity against two Gram negative bacteria (Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853) and two Gram positive bacteria (Staphylococcus aureus ATCC 25923 and Enterococcus faecalis ATCC 29212). The influence of complexes 1–10 and the free ligands on the catalytic peroxidation of the linoleic acid by the enzyme lipoxygenase (LOX) has been determined experimentally and theoretically.

Well-Defined, Molecular Bismuth Compounds: Catalysts in Photochemically Induced Radical Dehydrocoupling Reactions.

A series of diorgano(bismuth)chalcogenides, [Bi(di‐aryl)EPh], has been synthesised and fully characterised (E=S, Se, Te). These molecular bismuth complexes have been exploited in homogeneous photochemically‐induced radical catalysis, using the coupling of silanes with TEMPO as a model reaction (TEMPO=(tetramethyl‐piperidin‐1‐yl)‐oxyl). Their catalytic properties are complementary or superior to those of known catalysts for these coupling reactions. Catalytically competent intermediates of the reaction have been identified. Applied analytical techniques include NMR, UV/Vis, and EPR spectroscopy, mass spectrometry, single‐crystal X‐ray diffraction analysis, and (TD)‐DFT calculations.

Fluorescence Sensors for Bismuth (III) Ion from Pyreno[4,5-d]imidazole Derivatives.

Three pyreno[4,5-d]imidazole derivatives are synthesized and evaluated as fluorescent sensors for bismuth (III) ion. The target compounds are prepared in 55-86% yields from a condensation reaction between pyrene-4,5-dione and aromatic aldehydes. The compound bearing a phenolic group can selectively detect bismuth (III) ion via fluorescence enhancement with a detection limit of 1.20μm in CH3 CN-DMSO mixture and 3.40μm in 10% pH5 aqueous in CH3 CN-DMSO mixture. The sensing mechanism involving a formation of coordination complex is investigated by UV-VIS and fluorescence titrations, 1 H-NMR and the decomplexation of the bismuth complex by sulfide ion. The application of this sensor for quantitative analysis of spiked bismuth (III) ion in real water samples from two different sources is demonstrated.

Structural, optical, and magnetic properties of compositionally complex bismuth ferrite (BiFeO3)

Compositionally complex ceramics (CCCs) is an extended version of high entropy ceramics (HECs) concept where compositional space has been broadened by the inclusion of non-equimolecular compositions and relatively low entropy options to provide more flexibility in tuning the properties of materials. This study is the first experimental demonstration of the novel CCCs concept in multifunctional bismuth ferrite (BiFeO3). Compositionally complex bismuth ferrite (CCBFO) samples were prepared by conventional solid-state reaction method through the incorporation of five different cations in Fe sites, BiFe1–5xMoxTixZrxNixCexO3 (x = 0.01, 0.02, 0.03). Reitveld refinement reveals notable distortion in the rhombohedral R3c-type structure with a significant change in Fe–O–Fe bond angle from its ideal value of 180° to 100.2°. Mesoporous-type morphology with a substantial amount of interconnected porosity is observed from SEM micrographs. To prove the utility of the samples, optical and magnetic properties have been investigated. Bandgap value reduces to 2.12 eV from 2.86 eV with the increment of doping from 5 to 15%. M–H curve from VSM analysis indicates weak ferromagnetic behavior with narrow coercivity in all samples instead of ideal antiferromagnetism in BiFeO3. The highest saturation magnetization of 0.45 emu/gm is seen in 15%-doped CCBFO. These changes in properties are also in good agreement with the measured structural and morphological parameters. The obtained results suggest that CCCs concept can be effectively used to tune the properties of multifunctional ceramic oxides and careful selection of cations might improve the functionalities even to a new extent.

Bimetallic Pd-Bi/C Catalysts Prepared by Grafting of Complexes with O-Donor Ligands

Bimetallic carbon-supported PdBi catalysts were prepared by grafting. To do so a soluble complex of bismuth with exchangeable O-donor ligands was selected, and the carbon support was functionalized to increase the number of surface functions. The grafting procedure was carried out by contacting the various supports with solutions of Pd and/or Bi complexes, to allow ligand exchange reactions to take place between the complexes and the surface O-groups. The grafted fragments were then activated into carbon-supported nanoparticles, which were characterized to unravel the impact of grafting experimental variables on the physico-chemical characteristics of the materials obtained. The PdBi/C catalysts were finally tested in the archetypal glucose selective oxidation reaction, to assess the impact of those characteristics on the catalytic performance. It was found that simultaneous grafting gave larger nanoparticles than consecutive grafting, while higher number of stable surface functions allowed to obtain small and nicely distributed bimetallic nanoparticles. However, the surface functions were found to be deleterious for the catalytic activity, and the placement of the Bi promoter with respect to Pd active phase was identified as another key parameter for the activity, with grafting allowing to compare neatly samples where Bi is underneath, above or beside Pd.

Bismuth(III) complexes with pyrazineformamide thiosemicarbazones: Investigation on the antimicrobial and cytotoxic effects

Complexes [Bi(PzAm4DH)Cl2] (1), [Bi(PzAm4M)Cl2] (2), [Bi(PzAm4E)Cl2] (3), [Bi(PzAm4Cy)Cl2]⋅3H2O (4) and [Bi(PzAm4Ph)Cl2] (5) were prepared with 2-pyrazineformamide- (HPzAm4DH, L1), N(4)-methyl-2-pyrazineformamide- (HPzAm4M, L2), N(4)-ethyl-2-pyrazineformamide- (HPzAm4E, L3), N(4)-cyclohexyl-2-pyrazineformamide (HPzAm4Cy, L4) and N(4)-phenyl-2-pyrazineformamide (HPzAm4Ph, L5) thiosemicarbazones. L4 crystallized from methanol in monoclinic crystal system. All compounds were assayed for their cytotoxicity against SF-295 (glioblastoma multiforme) and HCT-116 (colon adenocarcinoma) human tumor cell lines and Mycobacterium tuberculosis H37Rv ATCC 27294 strain. Complexes 1–5 proved to have poor activity against the tumor cells at 5 μg/mL, whereas for complexes 4 and 5, coordination to Bi(III) was an effective strategy to increase the antimycobacterial activity of the thiosemicarbazones L4 and L5.

Synthesis, characterization and biological applications of bismuth(III) complexes with aroylthiourea ligands

This work describes the synthesis, structural characterization and biological applications of three new bismuth(III) complexes with aroylthiourea-based ligands: [Bi(La)3(HLa)] (1), [Bi2(Lb)4(μ-Lb)2]⋅2(C3H6O) (2), and [Bi6(μ-Lc)6(μ3-NO3)2(μ6-NO3)](NO3)3⋅4H2O (3), where HLa = N-benzoyl(N′,N′-diethylthiourea), HLb = N-benzoyl(morpholinylthiourea), and H2Lc = N2,N6-bis(diethylcarbamothioyl)pyridine-2,6-dicarboxamide. The ligands HLa and HLb were considered as monopodal, while H2Lc as bipodal. All compounds were characterized by melting point determination, Fourier-transform infrared spectroscopy (FTIR), proton proton and carbon-13 nuclear magnetic resonance spectroscopy (NMR), mass spectrometry (MS), elemental analysis (EA) and single-crystal X-ray diffraction (SC-XRD). Structural analysis showed that compound 1 was a mononuclear heptacoordinate complex, while compound 2 presented a dinuclear structure and compound 3 was built up by a hexanuclear framework. The proligands, the new complexes, and Bi(NO3)3⋅5H2O had their antibacterial activities evaluated against E. coli (ATCC 25922), S. aureus (ATCC 25923), and P. aeruginosa (ATCC 27853). The in vitro disk-diffusion (DD) method showed the ability of compound 2 to inhibit two types of bacteria (P. aeruginosa and S. aureus). In the results of minimum inhibitory concentration (MIC), all complexes showed significant activity against the tested microorganisms except for compound 1. The inorganic salt used for comparison showed antibacterial activity only against P. aeruginosa and the ligands showed no apparent activity. Compound 2 presented the best antibacterial activity among the tested substances, and its performance was remarkable even when compared to other similar compounds found in the literature, attesting the importance of targeting bismuth(III) aroylthioureas for further research on new drugs development.

Morphological variations in Bi2S3 nanoparticles synthesized by using a single source precursor

A simple solvothermal decomposition of bismuth dithiocarbamate complex in oleylamine, oleic acid, and hexadecylamine at 180 °C, yielded bismuth sulphide nanomaterials of different morphologies represented as Bi2S3(OAm), Bi2S3(OAc) and Bi2S3(HDA) respectively. The bismuth complex, used as the single source precursor, was synthesized and characterised by elemental analysis, FTIR, and NMR spectroscopic techniques. The spectroscopic and micro analysis confirmed the proposed compound, while the as-prepared nanoparticles were characterized using UV-visible spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy dispersive spectrometer (EDS). The effects of the different solvent media on the structural properties of the obtained Bi2S3 were investigated. An orthorhombic phase bismuthinite of varying intensities were obtained, with an indication that a bias of orientations existed in the (2 1 1) crystallographic planes in the Bi2S3(OAm) compared to the characteristic (1 3 0) diffraction peak of Bi2S3. The microscopic analysis showed a correlation between the nanoparticles' morphology and the type of solvent used, which also implied that the properties of Bi2S3 were affected by the solvent medium.

Tweaking the Charge Transfer: Bonding Analysis of Bismuth(III) Complexes with a Flexidentate Phosphane Ligand.

To account for the charge transfer and covalent character in bonding between P and Bi centers, the electronic structures of [P(C6H4-o-CH2SCH3)3BiCln](3–n)+ (n = 0–3) model species have been investigated computationally. On the basis of this survey a synthetic target compound with a dative P→Bi bond has been selected. Consecutively, the highly reactive bismuth cage [P(C6H4-o-CH2SCH3)3Bi]3+ has been accessed experimentally and characterized. Importantly, our experiments (single-crystal X-ray diffraction and solid-state NMR spectroscopy) and computations (NBO and AIM analysis) reveal that the P···Bi bonding in this trication can be described as a dative bond. Here we have shown that our accordion-like molecular framework allows for tuning of the interaction between P and Bi centers.

Synthesis, crystal structure, antibacterial, antiproliferative and QSAR studies of new bismuth(III) complexes of pyrrolidineditiocarbamate of dithia-bismolane and bismane, oxodithia- and trithia-bismocane

Four new bismuth(III) complexes; (CH2S)2Bi[S2CN(CH2)4] (2), CH2(CH2S)2Bi[S2CN(CH2)4] (3), S(CH2CH2S)2Bi[S2CN(CH2)4] (4), O(CH2CH2S)2Bi[S2CN(CH2)4] (5) were prepared from the reaction of the sodium salt of pyrrolidine-dithiocarbamate (1) with four chloro-dithia-bismuth(III) compounds containing five-, six- and eight-membered heterocycles. The complexes were characterized by elemental analyses, infrared, and 1H and 13C NMR spectroscopy. In addition, the single crystal X-ray structures of 2–4 were obtained, showing an asymmetric bidentate coordination mode of the dithiocarbamate ligand moiety. The metal center in 2 and 3 is tetracoordinated, while in 4 a pentacoordinate metal center is observed, the latter is achieved through the 1,5-transannular Bi⋯S interaction, which is common in these types of metallocane rings. Antibacterial assays showed that 2–5 were active in ATCC and clinical isolated strains. Antiploliferation assays were carried out showing high antiproliferative effect against breast cancer cell lines, in vitro. A QSAR model employing quantum global and local chemical descriptors was constructed to gain further insight into their antibacterial activity.

Synthesis, physical characterization, thermal studies, biological activities and DFT computations on the molecular structure and vibrational spectra of [C7H12N2]2Bi2Br10·4H2O compound

A new bismuth (III) complex, 2,4-diammonium toluene decabromodibismuthate (III) tetra-hydrate, was synthesized and its structure was determined. Bismuth complex crystallizes in the monoclinic system with the P21/c space group. The cohesion between [C7H12N2]2+ cations, [Bi2Cl10]4- anions and water molecules is ensured by N–H⋯Br, N–H … Ow and Ow-H…Br hydrogen bonds that build a three-dimensional network. The NMR spectra shows the presence of one organic group C7H12N2, which is in agreement with the XRD structure. The optimized molecular structure and vibrational frequencies were calculated by the Density Functional Theory (DFT) method using the B3LYP function with the LanL2DZ basis set. On the basis of the comparison between calculated and experimental results, assignments of the fundamental vibrational modes are discussed. Besides, the electronic properties HOMO and LUMO energies were measured by TD-DFT approach. Their values indicate that the energy gap reflect the chemical stability and biological activity of this molecule. In this regard, the biological study focused on the antioxidant and antibacterial activities of bismuth (III) complex and its organic molecule have been investigated. These results showed that synthesized compound exhibit significant antioxidant and antibacterial activities. Moreover, the thermal analysis of the title compound between 200 and 500 ​K have been occurred and revealed one phase transition at 360 ​K. Furthermore, to discuss the mechanism of this phase transition in this material, a dielectric study of the title compound has been effectuated.

Sorption of bismuth(iii) and its chloride complexes with 2-aminopyrimidine cation on hydroxyapatite of various textures

Specific features of the interaction between bismuth(iii) and hydroxyapatite (HAP) of various morphologies during its sorption and co-crystallization binding were revealed. The obtained sorption isotherms nearly coincide with each other regardless of the HAP type used and cannot be described in terms of the Langmuir or Freundlich models. Bismuth can form the intrinsic phase of bismuth phosphate due to the chemical or topochemical reaction with HAP when the sorption method is used. In the case of co-crystallization binding of bismuth ions, the morphological modification of HAP occurs. The bismuth complexes with aminopyrimidine in neutral and weakly acidic solutions are readily hydrolyzed to form a precipitate, and no binding with HAP occurs.

Ultralow Thermal Conductivity and Thermoelectric Properties of Rb2Bi8Se13

Complex bismuth chalcogenides are narrow band gap semiconductors with intrinsic low thermal conductivity, which exhibit high potential as highly efficient thermoelectric materials. Here, we assess the basic thermoelectric properties of polycrystalline Rb2Bi8Se13 in the temperature range 300–823 K as well as performance-optimizing strategies. We find that the as-made bulk samples are single phase with the monoclinic crystal structure (P21/m) and crystallize in layer morphology. The pristine sample exhibits an exceedingly low lattice thermal conductivity of 0.6–0.46 W·m–1·K–1 at 300–823 K, which derives from strong lattice anharmonicity, large Grüneisen parameters, and low phonon velocities induced by the complex crystal structure with heavy atom Bi and a large unit cell. The Cl doping successfully enhances the carrier concentration in Rb2Bi8Se13 with a negligible impact on the electronic band structure, displaying common doping behaviors. Se vacancy, on the contrary, leads to n-type doping and enhances the effective mass and power factors more significantly. Consequently, a maximum ZT of ∼0.75 at 823 K for the 0.3% Se-vacancy-doped sample is obtained.

Room Temperature Synthesis and Characterization of Novel Bi(III) Complex with 2-Amino-3- Carbomethoxy-4,5,6,7-Tetrahydrobenzo[B]Thiophene as Potential Antimicrobial Agent

A novel bismuth(III) complex with 2-amino-3-carbomethoxy-4,5,6,7-tetrahydrobenzo[b]thiophene (ACTT) as a ligand have been synthesized. The novel complex was characterized on the basis of its IR, NMR, elemental analysis and MS spectral data. It was found that the ligand behaves as a monodentate chelating agent and bonds to the metal ion through the nitrogen atom of the amino group to form the [BiIII(ACTT)6]Cl3 complex. The new complex compound displayed significant antimicrobial activity (MIC = 8-32 µg/mL) against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Shigella flexneri, Candida albicans, Candida tropicalis and Cryptococcus neoformans.